This invention relates to apparatus for providing a permanent indication of the maximum pressure of gas in a system.
Presently, if failure of a pressure vessel occurs, suitable evidence is not available in many cases to indicate whether the failure may have been caused by over-pressurization or is due to other factors. Devices such as direct reading gages, relief valves, and recording devices mounted externally in the system are usually lost or destroyed when an explosion has occurred. Determination of the cause of the failure depends in such cases on metallurgical or physical inspections of the remains of the vessel and are often not conclusive.
Similarly, when a vessel is returned for the standard 5 year inspection, a reliable record is often not available to indicate the complete history of pressures to which the vessel has been exposed. If such data were available, it would be possible to select certain vessels which have been exposed to higher than normal service pressures for additional, more stringent screening tests, such as ultrasonic inspection.
Apparatus for indicating the maximum force exerted on a structural member by using the Brinell principle is shown in Swiss Pat. No. 571,219 and French Pat. No. 2,253,209. These patents do not suggest that such apparatus could be used to indicate gas pressure or how this could be done.
It is, therefore, the primary object of this invention to provide apparatus utilizing the Brinell principle for indicating the maximum pressure of gas in a system.